1. Field of the Invention
The present invention relates to a presentation system, a material (document) presenting device, and a photographing device for presentation.
2. Description of the Related Art
In a presentation, reference images may be displayed to an audience by displaying documents photographed by a document photographing apparatus on a screen, by reflecting a display of a personal computer on a screen, and by other methods. A laser pointer which indicates a point on the image on the screen by projecting a laser beam is often used. A laser pointer of this type has, however, the following disadvantages. Shaking greatly and adversely influences the pointing operation, thereby making the point unstable. Also the laser beam may be erroneously projected to be hazardously incident on the eyes of the audience. To overcome these disadvantages, the applicant proposed, in Japanese Patent Unexamined Application Publication No. 2001-299262, a system in which a presenter virtually performs a pointing operation on a virtual screen generated near a presenter, using a pointing mark, a camera photographs the presenter's actions, and the pointing mark is reflected as a point image on a projected image on a screen.
In the improved technique described above, however, the pointing operation is indirect. Due to this, it is difficult to indicate the point swiftly, and it is insufficient to suppress shaking.
In recent years, material (document) presenting devices are used in presentations, instead of OHPs (overhead projectors) which were widely used. A material (document) presenting device has a dynamic image camera, such as a video camera, which recognizes the materials as objects. Some of the material presenting devices are equipped with a material mounting pedestal on which materials are mounted. These material presenting devices are used to project a material image photographed by a camera, from a projecting device, for example, a liquid crystal projector, onto a screen.
In a presentation, the presenter who is explaining often explains by indicating (pointing to) a specific part. In this case, the presenter indicates the part by directly touching the material with a pen or an indication rod, by using a digitizer as an external device, or by other methods.
However, the method of indicating a part by directly touching the material causes a problem as described below. That is, the image of the material cannot be clearly shown since the shadow of the indication rod or the hand of the presenter falls onto the screen. On the other hand, although this problem does not occur when using a digitizer, it is necessary to buy the digitizer separately. Due to this, the material presenting device is caused to be larger, and new problems, such as storing the device, thereby occur.
In a presentation, a material presenting device may be used as one of the devices for projecting an image onto a screen. For example, as disclosed in Japanese Patent Unexamined Application Publication No. 2000-115603, a material presenting device may be equipped with a camera above a material mounting pedestal, the material prepared by the presenter and/or the presenter is photographed by the camera, and the photographed image is projected onto the screen.
According to the above-described material presenting device, the body of the camera is supported by an oscillating mechanism and the photographing direction of the camera is switched between the material direction and the presenter direction. With this structure, however, the harness of the camera may be twisted and broken. In addition, the material presenting device may be large since the oscillating mechanism for tilting the body of the camera is complicated.
In a presentation, a material presenting device may be used as a device for projecting an image onto a screen. The material presenting device may be equipped with a camera photographing a material and a display on a material mounting pedestal (for example, Japanese Patent Application Publication No. 3201707). According to the material presenting device, a material such as a document is placed on the material mounting pedestal, and the presentation can be performed while the photographed image of the material by the camera is projected onto the screen. In addition, the image photographed by the camera can be displayed on a display.
According to the above-described material presenting device, the number of switches for indicating or selecting functions increases as the number of functions increases. Therefore, the manufacture of the device incurs high cost, and it is difficult for the operator to understand the operating method thereof, whereby the operator may easily make mistakes in the operation. Thus, displaying the setting menu was proposed so as to reduce the number of switches. However, displaying the setting menu requires a setting place for an input device such as a mouse, a keyboard, or a touch panel, for indicating or selecting on the displayed setting menu. In addition, the manufacturing cost is increased since the touch panel is expensive.
Various safe pointing systems have been proposed, instead of one using a laser pointer, because a laser beam may be erroneously projected to be hazardously incident on the eyes of the audience. The applicant proposed, in Japanese Patent Unexamined Application Publication No. 2002-216470, a system in which a presenter virtually performs a pointing operation on a virtual screen generated near a presenter, using a pointing mark, a camera photographs the pointing mark, and the coordinates of the pointing mark on the virtual screen are calculated, a point image is generated on the coordinates, and the point image is synthesized with a material image projected onto a screen. According to the system, the presenter virtually performs a pointing operation on the virtual screen, using the pointing mark, whereby the point image is generated on the screen as if the presenter performed pointing on the screen.
In the above system, the pointing mark is positioned one by one at two reference points which are the relative diagonal points of the virtual screen, the camera photographs the relative reference points, and the coordinates of the virtual screen are generated based on these reference points. In this case, in order to clearly photograph the pointing mark, the pointing mark is composed of an emitting object which emits light at a specific wavelength (for example, infrared light). On the other hand, an optical filter for allowing infrared light to pass therethrough, which enables photographing of the pointing mark, is removably provided in the photographing optical path. The optical filter is placed in the photographing optical path when the virtual screen is generated. In addition, while the pointing operation is performed using the pointing mark, the optical filter is placed in the photographing optical path of the camera, so that the pointing mark is clearly photographed, and the background is not projected onto the screen.
In normal photographing, such as photographing the material or the presenter, the optical filter is removed from the photographing optical path of the camera. On the other hand, in generating the virtual screen or performing a pointing operation, that is, photographing the pointing mark (photographing infrared light), the optical filter is placed in the photographing optical path of the camera. Thus, the optical filter must be removably placed in the photographing optical path. The operation of the optical filter is troublesome if the operation is performed by hand. The structure of the device is complicated if a driving mechanism is provided and, moreover, the operation is electrically-driven under remote control. In addition, in both cases, the operation is time consuming, and ease of use of the system is not satisfactory.